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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

24381 results found.

  1. GRB 070510: Swift detection of a possible burst
  2. RHESSI Spectrum of GRB070508
  3. GRB 070509, Swift-BAT refined analysis
  4. GRB 070508: Suzaku/WAM observation of the prompt emission
  5. GRB 070509: ROTSE-III Optical Limits
  6. GRB070508: Swift/UVOT Observations
  7. GRB 070508, SMARTS optical afterglow observation
  8. GRB 070508, Swift-BAT refined analysis
  9. GRB 070508: Multicolor optical observations and possible redshift limit
  10. GRB070412: MAGIC telescope GeV observation
  11. GRB 070506, Swift-BAT Refined Analysis
  12. GRB070429B: VLT observations
  13. GRB 070309: Swift-XRT afterglow confirmation
  14. Swift/UVOT observations of GRB070429B
  15. GRB 070429B, Swift-BAT refined analysis
  16. Swift/UVOT observations of GRB070429A
  17. GRB 070429A, Swift-BAT refined analysis
  18. GRB 070429B: ROTSE-III Optical Limits
  19. GRB 070429: ROTSE-III Optical Limits
  20. GRB 070427, Swift-BAT Refined Analysis
  21. GRB 070411: Late-time Keck imaging
  22. GRB070419B: Suzaku WAM observation of the prompt emission
  23. GRB 070420, SMARTS optical/IR afterglow observations
  24. GRB 070411, deep LBT photometry
  25. GRB 070411: break in the optical light curve
  26. GRB 070420 Swift-BAT Refined Analysis
  27. GRB070419A: Kuiper Optical detection
  28. GRB 070419A: MARGE Observations
  29. GRB 070420: Faulkes Telescope South Observations
  30. GBR 070419A: Swift/XRT refined analysis
  31. GRB 070420: NIR and optical afterglow confirmed
  32. GRB 070419A: MITSuME Okayama Observations
  33. GRB 070419B, Swift-BAT refined analysis
  34. GRB 070419A Swift-BAT Refined Analysis
  35. GRB 070419A: RAPTOR Detection of Early Emission
  36. GRB 070419A: Faulkes Telescope North Optical Observations
  37. GRB070419A, optical observation
  38. GRB 070419: P60 Confirmation of Optical Afterglow
  39. GRB 070419A: ROTSE-III Optical Limits
  40. GRB 070418: Optical and IR observations with KANATA
  41. Trigger 276045: Swift detection of a possible burst
  42. IBAS Alert n.4202: not a real GRB
  43. GRB 070318, SMARTS optical/IR afterglow observations
  44. GRB070412: Swift UVOT observations
  45. IBAS Alert n.4199: Not a GRB
  46. GRB 070412, Swift-BAT refined analysis
  47. GRB 070412 Liverpool Telescope optical limit
  48. GRB 070411: Optical photometry at Crni Vrh
  49. GRB 070411, Swift-BAT refined analysis
  50. GRB 070412: Swift detection of a burst
  51. GRB 070411 : Liverpool Telescope Observations
  52. GRB 070411: ROTSE-III Detection of Optical Counterpart
  53. GRB 070406, Swift-BAT refined analysis
  54. GRB 070406: Correction to the optical candidate in GCN6253
  55. GRB 070406: Gemini South Imaging and XRT analysis
  56. GRB 070406: NOT observations
  57. GRB 070406: The exprosure time of Xinglong TNT optical Upper Limit
  58. GRB 070402: Suzaku WAM observation of the prompt emission
  59. GRB 070328: Suzaku WAM observation of the prompt emission
  60. INTEGRAL ToO Observation of SGR1806-20
  61. UVOT observations of GRB070330
  62. GRB 070330, Swift-BAT refined analysis
  63. GRB 070330, SMARTS optical/IR observations
  64. GRB 070330 - Watcher Observations
  65. GRB 070328: pseudo-z~2.75 from spectral parameters of the prompt
  66. Konus-Wind observation of GRB 070328
  67. long burst from SGR 1806-20 detected on March 26
  68. GRB 070328, Swift-BAT refined analysis
  69. GRB070220: optical observations
  70. GRB070208: optical observations
  71. GRB070318: Swift UVOT indicates unusual optical/UV afterglow
  72. Short-Hard GRB 070209: PROMPT Observations
  73. GRB 070318: absorption-line redshift
  74. GRB070318: Swift UVOT continuing observations
  75. GRB 070318, Swift-BAT refined analysis
  76. IBAS Alert n. 4176: not a GRB
  77. GRB 070311: Tautenburg sees afterglow fading
  78. IBAS Alert n. 4169: not a GRB
  79. GRB 070311: Optical observation.
  80. GRB 070309: variability of the XRT afterglow candidate
  81. GRB 070311: RAPTOR Detection of Optical Emission
  82. GRB 070311: MDM Optical Detection
  83. GRB 070311: MITSuME Okayama Optical Observation
  84. GRB 070311: Swift-XRT refined analysis
  85. GRB 070311: REM candidate afterglow
  86. GRB 070311: a long GRB detected by INTEGRAL
  87. GRB060901: Candidate optical afterglow
  88. GRB 070309: A long GRB detected by INTEGRAL
  89. GRB 070125: X-ray light curve analysis
  90. IBAS Alert 4162: Not a GRB
  91. GRB 070306: NOT observations
  92. GRB 070306, Swift-BAT refined analysis
  93. GRB 070306: XRT Team Refined Analysis
  94. GRB 070306: Optical and IR observations with KANATA
  95. GRB070227: Swift-XRT refined analysis
  96. GRB 070125, deep late-time optical observation
  97. GRB 070223: Optical Observations
  98. GRB 070227, Swift-BAT refined analysis
  99. GRB 920925C: optical afterglow candidate
  100. IBAS Alert n. 4144: not a GRB

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